US2428360A - Electrical guidance system for surface vessels - Google Patents

Description

Oct. 7, 1947. E. N. DINGLEY, JR 2,423,360

ELECTRICAL GUIDANCE SYSTEM FOR SURFACE VESSELS Filed Jan; 16, 1945 2 Sheets-Sheet 1 2 Qua/mm? I wae/za/vmL INVENTOR EDWARD N. DINGLEY, JR.

ATTORNEY Oct, 7, 1947. E. N. DINGLEY, JR I 2,428,360

ELECTRICAL GUIDANCE SYSTEM FOR SURFACE VESSELS Filed Jan. 16, 1945 2 Sheets-Sheet 2 INPUT l INPUT fl F -6\' /7-nm=z IFIEB lz olgTPpT OUTPUT FIG. 3

INVENTOR EDWARD N. DINGLEY, JR.

ATTORNEY Patented Oct. 7, 1947 s'rA'ras PATE'T ELECTRICAL GUIDANCE SYSTEM FOR SURFACE VESSELS (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) 2 Claims.

1 courses or channels may be navigated in fog or darkness.

Another object of my invention is to provide portable equipment suitable for rapid installation aboard vessels and easy removal therefrom, which will at all times make possible the determination, by the navigator or pilot of the vessel of the exact position of the vessel relative to a predetermined course or channel.

Other and further objects of my invention will be understood from the following specification and by reference to the accompanying drawings, in which:

Fig. 1 is a plan view of a channel provided with a guidance cable;

Fig. 2 is a side elevation of a portion of the channel provided with a guidance cable; and

Fig. 3 is a circuit diagram of one embodiment of my invention.

Fig. 1 represents the plan view of a channel wherein the singl conductor armored cable I is laid on the bottom of the channel to be navigated. At one end of the cable, an alternator 2 provides an alternating potential between the center conductor and the armor of cable I thus causing an alternating current flow through cable 1 which has its inner conductor connected to its armor at the end opposite from the generator. An alternating current of 5 amperes at a frequency of 500 cycles per second flowing in cable I has been found to be satisfactory for guidance purposes as stated in two articles on the subject published in the Proceedings of the Institute of Radio Engineers. vol. 9, No. 4, August 1921, PP273, and vol. 10, No. 1, February 1922, PP3. The power required to establish such a current is relatively small. For example, the

2 500 C. P. S. characteristics per 1000 feet of U. S. Coast Guard type 111 single conductor No. 8 AWG armored submarine cable are as follows: 1.35 ohms loop resistance, 22? microhenries loop inductance, 0.037 microfarad capacitance, 214 micromhos shunt conductance, 114e ohms surge impedance. The input impedance of a 174,000 foot length with the far end short circuited is 129eohms or 103-778 ohms. With a 24.8 millihenry inductor in series with the input to the cable, the load on the generator will be 103+9'0 ohms. For a cable input current of 5 amperes, the generator potential must be 515 volts and the generator output power must be 2575 watts. The current at the short circuited end of the cable will be 3.2 amperes or 64% of the input current.

My invention deals with means for detecting and utilizing the magnetic fields surrounding the guidance cable I.

In Fig. 2 there is shown a side elevation of a portion of the cable I together with a surface vessel 3 having mounted thereon, preferably protruding beyond-the bow, two loops 4 and 5, of which, loop 4 is vertical and lying in the fore and aft plan and loop 5 is horizontal. It is preferable, but not mandatory, that the plane of loop 4 should bisect the plane of loop 5.

Loops 4 and 5 each consist of approximately 1000 turns of small gauge insulated wire encased in waterproof frames. Each loop has a diameter of approximately 2 feet.

In Fig. 3. the loops 5 and 4 are shown connected, by appropriate wires, respectively to the input terminals of the linear audio frequency amplifiers 6 and 1. These amplifiers are identical and may be of any conventional type such.

as the one disclosed in U. S. Patent 2,338,100. It is preferable to use amplifiers which are tuned to bthe frequency of the current in the guidance ca le.

As shown in Fig. 3, the output of amplifier 6 is connected to the primary of isolating transformer 8 and the output of amplifier I is connected to the primary of isolating transformer 9. The secondary terminals of transformer 8 are connected to opposite corners of a bridge rectifier l0 and the secondary terminals of transformer 9 are connected to the other two opposite corners of the bridge rectifier Ill. The center 3. taps of secondary windings of transformers 8 and 9 are connected together through the zerocenter D. C. current indicating instrument II.

The output terminals of amplifier I are shown also connected to alternating current voltmeter [2.

It is well known to those skilled in the art that when instrument II is connected as shown in Fig. 3, its pointer will deflect from its normal center scale position by an amount proportional to the product of the in-phase components of the secondary voltages of the transformers 8 and 9. In consequence of the fact that amplifiers B and I are linear or constant in gain over wide ranges of input voltages, the deflection of the pointer of instrument II will be proportional to-the product of the in-phase components of the voltages induced, in loops 4 and 5, by the alternating magnetic field surrounding the guidance cable I.

Whenever the vessel 3 is directly above the cable I with its keel parallel to the length of the cable, loop 4 will link with a maximum number of flux lines and its induced voltage will be maximum while loop 5 will link no flux lines and its induced voltage will be zero. The product of a finite voltage multiplied by zero equals zero and in consequence the pointer of instrument II will not deflect but will point directly downward towarckthe cable.

If the vessel is making a. course parallel -to but on the right hand side of the cable, the voltage induced in loop 4 will be slightly diminished but a finite voltage will beinduced in loop 5.

selected, the pointer will point to the left in the direction of the cable. If the vessel is making a course parallel to but on the left hand side of the cable, the voltage in loop 5 will be finite and of a phase opposite to that induced in the previous instance and in consequence the pointer of instrument Ii will point to the right in the direction of the cable.

By means of the apparatus described thus far, I provide an indicating instrument which always points in the direction of the piloting cable. This indicating means may be made as sensitive as desired by increasing the gain of amplifiers 6 and 1. Full scale deflection may be obtained if the vessel deviates as little as a foot or two from a position directly above the cable or the sensitivity may be reduced, if desired, to obtain full scale deflection if the vessel deviates 25 or50 feet either side of the cable.

The practice of this invention is not limited to the use of the bridge rectifier II). There are other circuits well known to those skilled in the art which will cause an instrument pointer to deflect an amount proportional to the product of the in-phase components of two alternating voltages.

The A. C. voltmeter i2 is connected to the output terminals of amplifier I and is adjusted to deflect full scale when the vessel is directly over the guidance cable under ,which conditions, maximum voltage is induced in loop 4. As the vessel departs from a position directly above the cable, the voltage induced in loop 4 diminishes and the deflection of the pointer of instrument [2 diminishes proportionally. Thus instrument I 2 provides an indication of the approximate distance from the vessel to the cable and it m y be calibrated in feet or yards if desired. Instrument i2 is of particular value in case the vessel has departed beyond the effective fleld of the cable. In such cases, zero voltage will be induced in both loop 4 and 5 and the pointer of instrument II will point vertically downward as if the vessel were directly over the cable. In such a case, instrument l2 will show that the vessel is 'at an infinite distance from the guidance cable.

The detecting and indicating equipment described herein may be designed to be portable in order that it may accompany the harbor pilot as he boards and leaves a vessel. It is preferable that the ampliflers 6 and 1 and the transformers 8 and 9 and the bridge rectifler Ill be installed in a single waterproof case which may be placed in the bow of the vessel near the loops 4 and 5 in order that the loop leads may be short. The indicating instruments H and I! may be mounted in a light carrying case which may be placed on the bridge near the helmsman and the instruments may be connected, by means of portable rubber-covered cables temporarily laid on deck, to the rest of the equipment located near the bow.

. The voltage induced in loops 4 and 5 is due length of guidance cable beneath and astern oi the vessel contributes little to the voltage induced in loops 4 and Ii because of the shielding I efl'ect of the steel hull of the vessel. For this reason it is preferable to extend loops 4 and 5 slightly beyond the bow rather than to mount them near ductor extending along the desired course of vessels, in circuit with said source; a vessel provided with a steel hull; coil means horizontally mounted on said vessel in a plane perpendicular to the fore and aft plane of said vessel and at a distance in front of the bow inductively coupled with whose secondary is connected to the remaining two opposite corners of saidbridge; a zero-center direct current visual indicating instrument center-tapped to the above secondaries; and an alternating current voltmeter, calibrated to indicate distance from said conductor, connected to the output of said second mentioned amplifier.

2. An electrical guidance system comprising a field, means for mounting said coils on said vessel in front of the bow thereof, means for amplifying the voltages induced in each of said coils, means for indicating the voltages induced in said vertical coil and means responsive to the product of th in-phrase components of said amplified voltages for indicating the position of said vessel with respect to said conductor.

EDWARD N. DINGLE'Y, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,589,398 Kelley June 22, 1926 2,166,991 Guanella July 25. 1939 1,787,992 McIlvaine Jan. 6, 1931 1 689292 ONeill Oct. 30, 1928' 736,432 Owens Aug. 18, 1903 OTHER REFERENCES Article, The Flux Navigator," Electronics, Feb.

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